铁树开花

tiěshùkāihuā

铁树开花 — tiěshùkāihuā

1. lit. the iron tree blooms (idiom); a highly improbable or extremely rare occurrence

   这种事情发生，真是铁树开花。 zhèzhǒng shìqíng fāshēng zhēnshì tiěshùkāihuā — It's really an iron-tree-blooming event that this happened.